build(deps): bump mini_racer from 0.19.2 to 0.20.0 in /docs/v3 (#4881)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

docs/v3/Gemfile.lock

@@ -108,11 +108,10 @@ GEM
     middleman-syntax (3.6.1)
       middleman-core (>= 3.2)
       rouge (~> 3.2)
-    mini_racer (0.19.2)
+    mini_racer (0.20.0)
       libv8-node (~> 24.12.0.1)
     minitest (6.0.1)
       prism (~> 1.5)
-    mutex_m (0.3.0)
     nokogiri (1.19.1-arm64-darwin)
       racc (~> 1.4)
     nokogiri (1.19.1-x86_64-darwin)